Question

Which of the following are dominant forms of hereditary traits in humans ?

1. Curly hair
2. Blue eyes
3. Thin lips
4. Dimpled cheeks
5. Rolling cheeks
6. Dark skin colour.

Answer 1

Dominant alleles

1. When two allelomorphic genes representing the alternatives of a character come together, usually one allele is expressed fully and the other is not expressed at all, then the alleles are called as dominant allele.
2. They are expressed in both heterozygous and homozygous conditions.

Recessive alleles

1. The allele that fails to express itself in the presence of its contrasting dominant allele.
2. They are expressed basically in homozygous conditions.

The dominant and recessive forms of hereditary traits are shown below in a tabular form:

Dominant	Recessive
Curly hair.	1.Blue eyes
2.Dimpled cheeks	2. Thin lips
3. Rolling tongue	3. Dark skin colour